Technical Field
The present disclosure relates to a controller and an internal combustion engine system.
Discussion of the Background
In the related art, for example, a controller for an internal combustion engine having the above configuration disclosed in Japanese Unexamined Patent Application Publication No. 2015-094288 is known. A compressor and a turbine of the supercharger are rotatably provided in an intake passage and an exhaust passage, respectively, of this internal combustion engine, and the compressor and the turbine are coupled to each other via a rotary shaft. Accordingly, an exhaust gas exhausted to the exhaust passage rotationally drives the turbine, and accordingly, the compressor rotates with the turbine, and a supercharging operation for boosting an intake air is performed. In addition, in this internal combustion engine, one of the intake passage and the exhaust passage is provided with a bypass line that bypasses the compressor or the turbine, and the bypass line is provided with a control valve for opening and closing the passage. The opening and closing of the control valve is controlled in order to control the boost pressure downstream of the compressor in the intake passage.
In a typical internal combustion engine connected to a multi-stage automatic transmission, if the transmission performs shift-up, the rotational speed of the internal combustion engine on the input side of the transmission is decreased to match a rotational speed according to a gear ratio of a shift stage after the shift. In addition, in order to reduce shift shock, a torque-down control is performed in which the torque is temporarily decreased by, for example, retarding the ignition timing. To perform such a torque-down control, in the above-described controller of the related art, the boost pressure is decreased by performing drive control to open a control valve during shift-up in the supercharging operation of the internal combustion engine. In addition, after the shift-up, drive control is performed to close the control valve, thereby increasing the boost pressure that has been decreased once already.